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6-6
FM 351 Positioning Function Module
EWA 4NEB 720 6001-02
6.1.2 Calling Functions
When you link the FM 351 into your program, please pay attention to the
following requirements.
The parameterization for the two channels in the FM 351 has been com-
pleted. That is, there is valid data in the CPU.
The channel DB is present and assigned appropriate to the configuration
of the system. That is, you have pre-assigned the channel DB for use with
the FM 351.
You have set up the FM 351 properly and optimized it.
The module is automatically parameterized by the system. The CPU loads all
data into the FM 351. The FM 351 checks the data and is parameterized if no
error occurs.
1. Switch the CPU from STOP to RUN.
2. The complete restart OB is run.
3. The CPU starts executing the program at the start of OB1.
Take note of the following rules for calling the FCs.
The relevant function block must be called separately for each channel.
Only link FCs into your program which you really need. Sharing the func-
tional features across many FCs helps to keep down the memory require-
ment for the applications.
Functions which write data must not be active simultaneously.
Functions which write data must remain called until the initiated job has
been completely processed.
The data must be valid. To ascertain this, interrogate the PARA bit from
the channel DB.
For each channel you must ensure that:
Only one mode block is called and is active.
In parallel to this, only one FC is called and active for writing data.
In parallel to this, one or more FCs are called and are active for reading
data.
Requirements
Loading Paramete-
rization Data into
the FM 351
Rules for Calling
the Functions
Centralized
Operation
Programming the FM 351
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